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Week 6
Mutations + proteins
| Question | Answer |
|---|---|
| Mutation defintion | Any permanent change in an organism's DNA |
| Point mutation definition | One or a small number of base changes (substitutions, insertions or deletions) |
| Substitution vs. insertion vs. deletion | Substitution: different base is substituted in Insertion: nucleotide is inserted in to DNA sequence Deletion: nucleotide is removed from DNA sequence |
| Silent vs. missense vs. nonsense mutations | Silent: no effect, will still code for same amino acid (redundancy in code) Missense: codes for differnernt amino acid Nonsense: changes amino acid into a stop codon |
| Non-frameshift vs. frameshift mutations | frameshift is caused by insertion/deletion (not in multiples of 3) leading to a very different potentially non-functional protein. non frameshift does not change the reading frame |
| Consequences of framshift mutations | non-functional proteins, ex. cancer or severe diseases |
| What is a spontaneous mutation? | random changes in an organisms genetic code not caused by external sources; mutation caused by errors in DNA replication or in cell division |
| Examples of physical + chemical mutagens | UV light, x-rays, gamma rays, pesticides, etc |
| 3 different types of mutations | small scale/point mutations, alterations in chromosome structure, and alterations in chromosome number |
| Causes of mutations | errors in DNA replication or in cell division, induced mutations caused by mutagens (ex. radiation + chemicals) |
| Most mutations are: | neutral or deleterious (harmful) |
| Inversion (in alteration in chromosome structure) | order of genes is changed; a segment of a chromosome breaks off, flips around, and rejoins |
| Translocation (in alteration in chromosome structure) | a section of chromosome breaks off and becomes attached to another chromosome (similar to crossing over) |
| Deletion (in alteration in chromosome structure) | a segment of chromosome is lost |
| Duplication (in alteration in chromosome structure) | a segment of chromosome is present in multiple copies |
| Fitness defintion | an organisms ability to survive + reproduce/pass on its genes (offspring must be viable as well) |
| Alteration in chromosome structure defintion | abnormal chromosome structure; results from larger scale changes in the chromosome bases (duplications, inversions, deletions + translocations) |
| Alteration in chromosome number defintion | abormal chromosome number; results from non-disjunction during meiosis (aneuploidy + polyploid) |
| What is meiotic non-disjuction? | When both homologs/sister chromatids move to the same pole of the parent cell; results in gametes that contain an extra chromosome (n+1) or lack 1 chromosome (n-1) |
| What is aneuploidy? | Cells that have too many or 2 few of a chromosome |
| Is an extra/missing chromosome likely to have any phenotypic effect in a diploid organism? | Yes highly likely |
| List examples of human disorders due to aneuploidy | Turner syndrome (45, XO), Klinefelter syndrome (47, XXY), albinism, huntington's disease, down syndrome |
| What is polyploidy + its consequences? | cells/organisms that contain more the 2 complete chromosome sets; common in plants + causes increased cell size, increased adaptibility/genetic variation + infertillity |
| How many chromosome would be in a trisomic, monosomic + triploid individual (normal 2n = 24) | trisomic: 25 chromosomes monosomic: 23 chromosomes triploid: 36 chromosomes |
| What is the importance of mutations? | they are the primary source of genetic variation, allow organisms to evolve + adapt to their enviroment, contribute to genetic diversity |
| Where must mutations take place to be transmitted to the offspring? | in the gametes/reproductive cells |
| Why are most mutations harmful? | all mutations are random, and even a little change could potentially cause a protein to stop functioning, cause diseases, and just disrupt the precise-ness that the proteins need to work properly |
| What are other sources of genetic variations? | sexual reproduction/random fertilizations + gene flow |
| Macromolecule definition | polymers built from monomers ex. protein polymer = polypeptides, monomers= amino acids |
| Amino acid definition + structure | Organic molecules with carboxly + amino groups. (contains amino group, carboxly group, side chain + central carbon) |
| How are peptide bonds formed between amino acids? | a bond (dehydration synthesis) forms between a carboxyl group of one amino acid + an amino acid of another (between C and N. NCC-NCC-NCC etc.) goes 5' to 3'/N to C'. they behave like double bonds, dont bend |
| Draw general structure of animo acid | not a card !!! |
| Which chemical groups form the backbone of a polypeptide + which ones form side chains | the animo + carboxyl groups form the backbone. various r groups form the side chains |
| How are the amino acids grouped into 4 types? | by the properties of the side chains; nonpolar, polar, acidic + basic |
| negative side chain = | acidic |
| positive side chain = | basic |
| uncharged side chain with oxygen = | polar |
| uncharged side chain with NO oxygen = | nonpolar |
| Oligipoptide definition | polymer of less then 50 amino acids |
| Polypeptide definition | polymer with more then 50 amino acids |
| Protein definition | any amino acid chain; but more formally the complete functional form of the molecule. each protein has a unique linear sequence of amino acids + that sequence determines a protein's 3D structure |
| Globular vs. fibrous proteins | Globular: highly folded 3D shape, water soluble, functional; ex. hemoglobin, enzymes Fibrous: elongated fibers/sheets, insoluble, structural support; ex. keratin |
| Primary structure definition | The unique sequence of amino acids in a protein. 2D line. fundemental to higher levels, a single amino acid change can radically alter function |
| Secondary structure definition | Formed by hydrogen bonds between the carboxyl group of one amino acid and the amino group of another amino acid (only backbone interactions) forms either a helices or b pleated sheets |
| Tertiary structure definition | results from interactions between r groups or between r groups + the peptide backbone; the backbone bends and folds contributing to 3D shape of the polypeptide |
| Quaternary structure definition | results from 2 or more polypeptide chains forming 1 macromolecule. |
| Protein folding | each protein has a characteristic shape necessary for its function; many proteins have a disordered shape when they are inactive; some proteins are regulated by controlling when or where they are folded into active shapes |
| Protein denaturation definiton | when a protein unravels and loses its 3D shape due to a change in pH, tempurature, salt conc., etc. primary structure ALWAYS stays intact; (only bonds in 2,3, + 4 are broken) denatured protein is biologically inactive |
| a helix vs. b pleated sheet | secondary structure shapes. a-helix: coil shape, more flexible, often found in globular proteins b-pleated sheet: zig zag/pleated shape, more rigid, often found in fibrous proteins |
| Enzymatic proteins (function + example) | selective acceleration of chemical reactions; ex. digestive enzymes that catalyze the hydrolysis of bonds in food molecules |
| Storage proteins (function + example) | storage of amino acids; ex. casein (milk protein) for baby mammals; plants have storage proteins in their seeds |
| Hormonal proteins (function + example) | coordination of an organisms activities; ex. insulin causes other tissues to take up glucose, thus regulating blood sugar concentration |
| Contractile + moter proteins (function + example) | movement; ex. motor proteins control undulations of cilia + flagella, actin + myosin proteins control contractions of muscles |
| Defensive proteins (function + example) | protections agaisnt disease; ex. antibodies inactivate + help destroy viruses + bacteria |
| Transport proteins (function + example) | transport of substances; ex. hemoglobin transports oxygen from the lungs to the body, other proteins transport molecules across cell membranes |
| Receptor proteins (function + example) | response of cell to chemical stimuli; ex. receptors built into the membrane of a nerve cell detect signaling molecules released by other nerve cells |
| Structural proteins (function + example) | support; ex. keratin (product of hair, horns + feathers) spiders use silk threads to make webs + collagen/elastin proteins provide a fibrous framwork in animal connective tissues |
| What structural levels are: 1. stabilized only by covalent bonds 2. stabilized by interactions between backbone elements 3. stabilized by interactions between side chains | 1. primary - covalent/peptide bonds between amino acids 2. secondary 3. tertiary |
| What stuctural levels are: 1. present in some proteins but not all 2. affected by denaturation (name some denaturing agents) | 1. quaternary 2. secondary, tertiary + quaternary - primary ALWAYS stays intact |
| What are enzymes? | a protein that functions as a (biological) catalyst (something that speeds up a reaction) |
| What is activation energy? | the minimum amount of energy it takes to activate/initiate a chemical reaction. lower EA = faster reaction |
| Draw a "progess of reaction vs. free energy" graph and be able to label reactants, products, transition state, EA, and free energy change | not a card !!! |
| Enzyme traits | they are protein catalysts; each enzymes is specfic to a particular chemical reaction + enzymes are niether consumed nor changed by the chemical reaction |
| Substrate definiton | The reactants in enzyme-catalyzed reactions. they bind via hydrogen bonding or other interactions with amino acid residues in the active site. Many enzymes undergo a shape change when the substrates are bound to the active site called "induced fit" |
| Active site definition | the locations on an enzyme where substrates bind + react |
| Explain induced fit model | during the enzyme-substrate interaction, the active site is able to change shape upon binding to substrate to catalyze the reaction more efficiently |
| Draw graphs of rate of reaction vs. tempurature + rate of reaction vs pH | tempurature: as tempurature rises kinetic energy increases, increasing chances of a successful collision between substrate/enzyme molecules = increased reaction rate peaking at an optimal temp pH: bell shape, enzymes rate of reaction peaks at an ideal pH |
| Cofactor vs. coezyme | cofactors: inorganic molecules; ex. copper, iron (stablize structure/assist in catalysts) coenzymes: organic molecules; ex, vitamins (move chemical groups between enzymes) |
| What are enzyme inhibitors? | molecule that binds to an enzyme + decreases or stops its activity by blocking the substrate from binding to the active site (can be temperary or permanent) |
| What type of inhibition is represented by allosteric interactions | non competitive interactions |
| 4 conditions that affect an enzyme's function | tempurature, pH, interactions with other molecules + modifications of its primary structure |
| 5 types of r-group interactions | hydrogen bonds, hydrophobic interactions, van der waals interactions, covalent disulphide bonds + ionic bonds |
| Why is feedback inhibition important? | maintains cellular homeostatsis, makes sure too much of a product isnt being made (saving energy) |
| What is the allosteric binding site for? | to regulate enzyme activity (molecules can change the shape to turn it on or off) |
| Competitive vs. noncompetitive inhibitors | comp: bind to the active site of an enzyme competing with the substrate (looks similar) non comp: bind to the allosteric site causing the enzyme to change shape making active site less effective or inactive; does not look similar |
Created by:
every_august
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